Pick a donor and a recipient blood type to see whether the pair works under standard ABO and Rh rules for red blood cell donation, including who O positive can donate to and receive from.
This reflects standard red blood cell donation compatibility rules. Actual transfusion decisions are always made by medical professionals with full cross-matching.
Who Can O Positive Donate To and Receive From?
O positive can donate red cells to O+, A+, B+ and AB+. It can receive from only O+ and O-, since those are the only donors whose lists include O+.
| Blood type | Can donate red cells to | Can receive red cells from |
|---|---|---|
| O- | All 8 types | O- |
| O+ | O+, A+, B+, AB+ | O-, O+ |
| A+ | A+, AB+ | O-, O+, A-, A+ |
| B+ | B+, AB+ | O-, O+, B-, B+ |
| AB+ | AB+ only | All 8 types |
How the Compatibility Check Works
It checks whether your recipient is on the donor’s fixed list. It is an educational reference, not a substitute for the lab cross-matching real transfusions always require.
Formula: Each blood type has a fixed list of recipient types it can safely donate red blood cells to, based on standard ABO/Rh rules: O- can give to all 8 types (the universal donor), O+ can give to O+, A+, B+, and AB+, A- can give to A-, A+, AB-, and AB+, A+ can give to A+ and AB+, B- can give to B-, B+, AB-, and AB+, B+ can give to B+ and AB+, AB- can give to AB- and AB+, and AB+ can only give to AB+ (the universal recipient). The calculator checks whether the chosen recipient type appears on the chosen donor’s list.
- Choose donor B+ and recipient O+.
- Look up the B+ list: B+ and AB+.
- O+ is not on it, so the result is Not Compatible.
- Donor blood type: the blood type of the person giving blood, chosen from O-, O+, A-, A+, B-, B+, AB-, or AB+
- Recipient blood type: the blood type of the person receiving blood, chosen from the same eight types
Example Pairs, Including Universal Donor and Universal Recipient
O- is the universal donor blood type and AB+ the universal recipient. Can B positive donate to O positive? No. Can AB positive donate to anyone? Only another AB+.
| Donor Type | Recipient Type | Result |
|---|---|---|
| O- | AB+ | Compatible |
| O+ | A- | Not Compatible |
| A- | AB+ | Compatible |
| B+ | O+ | Not Compatible |
| AB- | AB+ | Compatible |
| A+ | B+ | Not Compatible |
What This Tool Does Not Cover
It covers only the textbook ABO and Rh red cell rules, which is just part of what happens before a real transfusion.
- Hospitals crossmatch. Donor red cells are tested against the patient’s plasma to catch antibodies beyond ABO and Rh.
- Other antigen systems, such as Kell, Duffy and Kidd, matter for frequent transfusion patients.
- Plasma rules run in reverse. AB is the universal plasma donor while O negative is the universal red cell donor, so a red cell tool does not answer plasma questions.
- Pregnancy is separate. Rh-negative mothers carrying Rh-positive babies need specialist monitoring, which this calculator cannot assess.
If you are not sure of your type, a blood donation service or your doctor can tell you. The blood type article on Wikipedia explains the antigens involved. Use the results for education only; transfusion decisions belong to the medical team.
Common questions about blood type compatibility
Who can O positive donate to and receive from?
Under standard ABO/Rh red cell rules, O+ can donate to O+, A+, B+ and AB+. It can receive from only O+ and O-, because those are the only donor types whose lists include O+.What blood type can A positive receive?
A+ can receive red cells from O-, O+, A- and A+. B and AB donors carry the B antigen, so they are not on the list.Can B positive donate to O positive?
No. B+ red cells carry the B antigen, which an O+ recipient lacks, so the calculator shows Not Compatible. B+ can give only to B+ and AB+.Can AB positive donate to anyone?
No. AB+ blood carries both A and B antigens plus Rh(D), so as a red cell donor it can only go to other AB+ recipients. AB+ is the universal recipient, which is a different question from who it can give to.Can an Rh-positive donor give blood to an Rh-negative recipient?
Under standard Rh rules, no. Rh-positive blood is generally considered unsuitable for Rh-negative recipients because it can trigger an immune response, while Rh-negative donors can give to both Rh-negative and Rh-positive recipients of the same ABO group.Does this calculator replace the cross-matching done before a real transfusion?
No. This tool only reflects the general ABO/Rh compatibility rules for educational purposes. Real transfusions always require laboratory cross-matching and screening by qualified medical professionals before blood is given to a patient.Related Calculators
If you found this useful, other blood-related tools include the blood pressure tracker for logging readings over time, the blood sugar level checker, and the anemia risk calculator for a general look at iron-related risk factors.